Utilizing the combination of renal micropuncture techniques for the evaluation of nephron filtration rate and the respective determinants of glomerular ultrafiltration and immunologic and morphologic analysis, we plan to evaluate the specific roles of both cellular and humoral mechanisms in the production of immune injury within the glomerulus and the later stages of both antiglomerular basement membrane antibody (AGBM Ab) and immune complex renal disease in the Munich-Wistar rat. Evaluation of specific mediators of glomerular immune injury will be conducted in an acute model before and after the administration of AGBM Ab. The present protocol describes a method whereby all of the relevant factors which govern the process of glomerular ultrafiltration can be measured both before and after the induction of immune injury to the glomerulus. These factors include the rate of nephron plasma flow (rpf), the transglomerular hydrostatic pressure gradient (delta P), systemic oncotic pressure (pi A) and the glomerular permeability coefficient (LpA) utilizing micropuncture techniques. Evaluation by this acute physiologic method will allow us to determine the specific physiologic role of the following mediators of acute glomerular immune injury; 1) the role of the polymorphonuclear leukocyte, 2) the effects of the platelet, 3) the effects of associated cationic amines such as histamine and serotonin, 4) the mediators of complement dependent vasoconstriction and 5) the role of steric and mechanical effects of AGBM Ab on the endothelial damage that we have observed in this model. This physioloic approach to the evaluation of glomerular immune injury which has been described by us in recent publications has demonstrated that decreased in LpA and vasoconstriction can both contribute to the acute reduction in nephron filtration rate. Other studies are described which evaluate more chronic or subacute models of immune injury in both AGBM Ab mediated disease and a model of immune complex mediated renal disease. This physiologic study will be the first to comprehensively examine immune mechanisms with more quantitative and specific physiologic indicators of glomerular function.